1. Field of the Invention
The subject adaptive high-energy abrasive stream cutting system is generally directed to a system for performing high definition cutting or abrading of a workpiece. More specifically, the subject adaptive high-energy abrasive stream cutting system is one which delivers onto a workpiece a high energy abrasive cutting stream to form therein an instantaneous kerf of cut having a predetermined shape. It is a system which forms and optimally maintains the angular orientation of the instantaneous kerf of cut during the abrasive cutting stream""s cutting of or about a predefined pattern defined on the workpiece.
Various types of systems are known in the art which utilize abrasive fluidic streams to cut or abrade predefined patterns in or through even very hard and tough materials, like dense stone and steel, which are normally quite difficult to cut, let alone to precisely contour. Unlike sandblasting and other such types of systems for effecting broad surface treatment, high definition cutting systems generate highly focused, extremely pressurized fluidic cutting streams in order, for example, to very closely trace intricate prescribed patterns upon a workpiece. Given enough cutting pressure, highly intricate patterns can effectively be xe2x80x98carvedxe2x80x99 into even the hardest of workpiece materials using such systems.
Typically in those systems, a head assembly receives and pressurizes a stream of water or other suitable fluid material provided by a given source. The pressurized stream is then further pressurized by forced passage through a nozzling mechanism whereupon a suitably abrasive particulate material is drawn into the stream at a controlled concentration for commingled expulsion therewith onto a workpiece. The energy and resulting abrasiveness of the cutting stream thus expelled is sufficiently high to cut intoxe2x80x94and if desired, throughxe2x80x94the workpiece material. The abrasive cutting stream may thereafter be displaced along the workpiece to trace and cut one or more predefined patterns.
Common drawbacks to these systems and their numerous applications are many, howeverxe2x80x94not the least of which are the inefficient consumption of the energy harnessed in the cutting stream, and the inability to effectively accommodate cuts of varying intricacy along a given pattern. In such known systems for precise workpiece cutting applications, little if any attention has been placed upon the sectional contour of the generated high-energy abrasive cutting stream. Consequently, no significant effort has heretofore been madexe2x80x94at least not in cutting applicationsxe2x80x94to employ an abrasive stream shaped in sectional contour to anything other than a standard, substantially circular shape. Except where the pattern to be cut presents a circular concavity along the path of cut, then, presently known cutting systems invariably incur substantial waste in the generated stream""s cutting energy.
Where the cutting stream incorporates an abrasive particulate material, such known cutting systems wastefully consume greater amounts of the abrasive particulate material than necessary. Since the abrasive particulate material tends to be well dispersed throughout the cutting stream when entrained therein, the particulate material unnecessarily occupies that portion of the cutting stream failing to contribute a meaningful cut. Over the duration of an extended cutting process, the waste could accumulate to considerable amounts.
The resulting inefficiency is illustrated in FIGS. 10a and 11a, which show a circular stream section 1000 disposed in cutting position along variously configured peripheries 1100, 1120 of a pattern to be cut. The tangency of contact between the stream 1000 and the straight periphery 1100 necessarily limits the actual cutting action along the periphery 1100 to just the stream""s immediately proximate portion 1010. Where the object is simply a precise cut along this straight periphery 1100, then, it is only the immediately proximate portion 1010 of the stream 1000 which forms a cut of any real consequence. Unless the object includes cutting a particularly configured gap to immediately bound the pattern being cut, for instance, the cutting power of the stream""s remaining distal portions 1020 is essentially wasted. The stream""s wasted cutting power is all the more evident in FIG. 11a where the tangency of contact between the stream 1000 and the cut pattern""s periphery 1120 is accentuated by the convexity of this periphery 1120.
FIG. 12a illustrates other difficulties often encountered in the use of systems heretofore known when even a nominally intricate cut pattern 1140 is prescribed. Where, as illustrated, the prescribed cut pattern 1140 includes such features as a recessed periphery 1140a, the same cutting stream configuration used elsewhere along the cut pattern may not suffice in cutting the recess 1150 delineated by periphery 1140a. While the cutting stream 1000 may adequately cut along the pattern""s base periphery 1140b, it exceeds in diameter the width of the recess 1150 to be cut. It may be necessary in such instance, perhaps, to halt operation and make the required modifications to generate a finer cutting stream 1000xe2x80x2 before the recessed periphery 1140a could be fully cut. This may require a certain degree of re-tooling in many cases.
Given such impediments, high definition cutting of precisely defined workpiece patterns remains a considerable challenge in the art. Even where ample resources to eventually effect a precise cut and finish about intricately detailed patterns, the indiscriminate use of an abrasive cutting stream having a fixed sectional configuration and the retention of that abrasive cutting stream at fixed angular orientation during operation, often render the process unduly inefficient and labor/time intensivexe2x80x94prohibitively so, in some cases.
2. Prior Art
High energy abrasive stream cutting systems are known in the art, as are assemblies which define and expel a non-circularly shaped abrasive stream. The best prior art references known include: U.S. Pat. Nos. 3,109,262; 3,576,222; 4,555,872; 4,587,772; 4,669,760; 4,708,214; 4,711,056; 4,776,412; 4,817,874; 4,819,388; 4,848,671; 4,854,091; 4,913,353; 4,936,059; 4,957,242; 5,018,317; 5,018,670; 5,052,624; 5,054,249; 5,092,085; 5,144,766; 5,170,946; 5,209,406; 5,320,289; 5,469,768; 5,494,124; 5,584,106; 5,782,673; 5,785,258; 5,851,139; 5,860,849; 5,878,966; 5,881,958; 5,921,476; 5,992,763; 6,065,683; and 6,077,5152.
Such prior art references, however, fail to provide any system in which a high energy abrasive stream for precise cutting of predefined workpiece patterns is sufficiently shaped and angularly displaced in adaptive manner during operation. Where the abrasive stream is modified in form to something other than a circular or other such fixed sectional contour, the abrasive stream in known systems is invariably modified either for conditioning/treating the workpiece surface or for removing wide areas of workpiece material, not for precision cutting. The stream is, therefore, modified in those systems primarily for dispersive effect. Hence, there remains a need for a system which removes the considerable inefficiency and imprecision inhering in high-energy abrasive stream cutting systems heretofore known.
A primary object of the present invention is to provide a system for generating an abrasive cutting stream operable to cut about or along a predefined pattern on a workpiece in an energy efficient manner.
It is another object of the present invention to provide a system for generating and adaptively maintaining at an optimal angular orientation a high energy abrasive cutting stream which is displaced in accordance with a predefined cutting pattern.
It is yet another object of the present invention to provide a system whose cutting stream generates a kerf of cut having in sectional contour a preselected one of a plurality of predetermined shapes suitable to effect a precisely contoured cut along a pattern predefined on a workpiece.
These and other objects are attained by the subject system for delivering onto a workpiece a high energy abrasive cutting stream. The system generally comprises a head assembly for providing a pressurized fluidic stream; a nozzling unit coupled to the head assembly for nozzling the pressurized fluidic stream; and, an adaptive orientation assembly coupled to the nozzling unit. The nozzling unit is operable to expel a high energy abrasive cutting stream for cutting about or along a predefined pattern on the workpiece, and includes a nozzle member having a laminar inner wall surface defining a longitudinally extending passage. This passage terminates at an outlet portion which describes in sectional contour a predetermined shape such that, during operation, it serves to generate upon the workpiece a kerf of cut having a corresponding sectional contour. The adaptive orientation assembly is operable to displace the nozzle member in a manner adaptive to the position of the nozzling unit relative to the pattern predefined on the workpiece. The adaptive orientation assembly thus maintains the cutting stream within a predefined angular orientation range relative to predefined pattern.
In a preferred embodiment, the system also comprises an articulation assembly coupled to the nozzling unit for pivotally displacing the nozzle member about at least one transversely directed pivot axis during the relative displacement of the nozzling unit and workpiece one relative to the other. Also in a preferred embodiment, the system further comprises a controller coupled to the adaptive orientation assembly for automatically actuating the adaptive angular displacement of the nozzle member. The predetermined shape employed for the nozzle member passage outlet portion may include such non-circular shapes as square, rectangular, curved rectangular, elliptic, segmented annular, diamond-like, oval, oblong, curved oblong, teardrop-like, and keyhole-like shapes.